Tanks, canisters, cylinders, and other vessels (collectively referred to in this document as “canisters” for convenience) are commonly used in medical and healthcare settings, such as hospitals, clinics, and homecare facilities, for holding gases (such as oxygen) or other fluids and compounds. As canisters are handled and transported (such as being connected, disconnected, replenished, relocated within or between rooms, etc.), they are exposed to and make contact with personnel, healthcare providers, patients, equipment and devices, medical and laboratory materials and byproducts, etc. Such exposure and contact leaves canisters generally soiled and unclean, and results in contamination of canisters with chemical and biological hazards, bodily fluids, and other foreign or undesirable substances. This facilitates the spread of potentially harmful and dangerous compounds and microorganisms. Further, contamination of an improperly sealed or otherwise unprotected or breached canister could compromise the purity of contents inside the canister, or could blend or combine with the contents of the canister between the time it exits the canister and the time the contents are used or applied (such as by being administered to a patient). What is needed are protective covers that help “quarantine” canisters and reduce the spread of infectious disease by acting as a physical containment barrier against direct contact with the canisters.